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PubMed1989

The efficacies of pure LICAM(C) and DTPA for enhancing the elimination of plutonium-238 and americium-241 from rats after their inhalation as nitrate.

After the inhalation of 238Pu and 241Am as nitrate, the repeated administration of DTPA is far superior to that of LICAM(C) for enhancing their elimination from the body. The therapeutic efficacies of these chelating agents are however similar after intravenous injection of 238Pu as citrate. It is concluded that DTPA should remain the agent of choice for treating persons contaminated internally with transportable forms of these actinides.

Administration, Inhalation↗
PubMed2001

Size-fractionated plutonium isotopes in a coastal environment.

We have examined the distribution of individual Pu isotopes (239Pu, 240Pu, and 241Pu) in seawater from the Gulf of Maine (GOM). Samples were size-fractionated with a 1 kD cross-flow ultrafiltration (CFF) membrane. Subfractioned samples were radiochemically purified and Pu isotopes were analyzed using a three-stage thermal ionization mass spectrometer (TIMS). To our knowledge, this is the first time that both size class and Pu isotopic data have been obtained for seawater samples. Within measurement uncertainties a single 240Pu/239Pu atom ratio of 0.18 was found for all sample collection depths and sample size fractions. This signifies a current, single Pu source in GOM waters, namely global fallout, and suggests that no measurable isotopic fractionation occurred during CFF processing. The majority of Pu was found in the low molecular weight fraction (< 1 kD). Colloidal Pu varied from 8% of the total in surface waters to < 1% in the deepest (250 m) seawater sample. Evidence suggests that the vertical distribution of Pu in GOM is primarily controlled by conservative mixing processes. The high Pu fraction found in the low molecular size fraction implies that most of the Pu is in the non-particle-reactive oxidized fraction, and is consistent with the conservative Pu behavior. The activity levels are in agreement with other studies which show a slow decrease in Pu with time due to continued mixing and relatively slow particle removal.

Atlantic Ocean↗
PubMed2001

Plutonium solubility in sediment pore waters.

Using in situ porous cup samplers, dissolved Pu concentrations have been measured over a year in the pore waters from two contrasting sites in the valley of the River Esk, North West England. In saltmarsh sediments, dissolved Pu represents approximately 1 part in 10(6) of the total inventory. The Pu concentration in solution is in the range 1.1-3.5 mBq l-1, varying by a factor of 3 in the course of the year. Most of the changes in dissolved Pu coincide with changes in dissolved Fe and Mn concentrations, with Pu being low in the summer months when Fe and Mn are high. Nevertheless, there are a number of factors which make it unclear as to whether these patterns might be related to seasonal redox changes in the saltmarsh. At the highly organic, reducing reedbed site, the proportion of Pu in solution is typically around 1 part in 10(3), proportionately much higher than in the saltmarsh, giving concentrations ranging between 9.0 and 28.5 mBq l-1, and are apparently maintained by complexation to dissolved organic matter. There is no obvious seasonal pattern at the reedbed site nor is there any relation to any of the dissolved species measured (Fe, Mn, Na, DOC).

Ecosystem↗
PubMed2002

Plutonium and americium inventories in atmospheric fallout and sediment cores from Blelham Tarn, Cumbria (UK).

The objective of this paper is to report on the results of a study of 238Pu, 239 + 240Pu and 241Am inventories onto Blelham Tarn in Cumbria (UK). The atmospheric fallout inventory was obtained by analysing soil cores and the results are in good agreement with the literature: 101 Bq m(-2) for 239 + 240Pu; 4.5 Bq m(-2) for 238Pu and 37 Bq m(-2) for 241Am. The sediment core inventory for the whole lake is compared to the atmospheric fallout inventory. The sediment activity is 60-80% higher than the estimated fallout activity, showing a catchment area contribution and in particular the stream input.

Americium↗
PubMed2002

The distribution and history of nuclear weapons related contamination in sediments from the Ob River, Siberia as determined by isotopic ratios of plutonium and neptunium.

Isotopic ratios of Pu and Np measured in sediment cores from 5 locations in the Ob River drainage basin show clear evidence of input from sources other than global fallout (non-fallout sources). Historical contaminant records obtained by combining isotopic ratio information with chronological information indicate that non-fallout inputs are from several sources that have varied significantly over the past 50 years. Unique isotopic signatures observed in sediments from tributaries that drain areas containing known or suspected sources of non-fallout contamination are used to identify the source of materials in sediments collected at downstream locations. These data can lead to a better understanding of the transport behavior, fate, and relative importance of particle reactive, weapons related contaminants originating from the nuclear facilities Mayak. Tomsk-7, and Semipalitinsk, which lie within the drainage basin. From our work to date, we draw the following conclusions: (1) Persistent non-fallout contamination is observed in the Ob River above its confluence with the Irtysh River, indicating contamination from the Tomsk-7 facility. (2) Non-fallout contamination in the Tobol River above its confluence with the Irtysh River indicates contamination from the Mayak facility. (3) Non-fallout contamination in the Irtysh River above its confluence with the Tobol River indicates contamination from the Semipalitinsk weapons test site. (4) The occurrence of isotopic ratios in Ob Delta sediments that are similar to those observed in source tributaries suggests that contamination from at least two sources has been transported along the length of the river system. (5) Global fallout, a result of high-yield atmospheric weapons tests conducted by the FSU and USA primarily, is the dominant source of Pu and Np to the region; however, there have been brief periods when inputs from non-fallout sources exceeded those from global fallout.

Environmental Monitoring↗
PubMed2003

Excess plutonium in soil near the Nevada Test Site, USA.

Two soil profiles were collected from undisturbed areas near the Nevada Test Site (NTS). The activity of 137Cs in the surface layer of the downwind Queen City Summit profile is three times higher than at the upwind site at Searchlight, NV (41.1+/-0.6 mBq/g vs. 13.0+/-0.4 mBq/g), and the 239,240Pu activity is 100 times greater (51+/-2 mBq/g vs. 0.52+/-0.03 mBq/g). An examination of the literature suggests that the 137Cs/239,240Pu and the 239,240Pu/238Pu activity ratios in soils and sediments from the northern hemisphere, due to fallout from atmospheric atomic weapons testing, have generalized values of 36+/-4 and 30+/-4, respectively (as of 1 July 1995). Deviations from these values may indicate possible contamination by sources other than fallout. Data from the surface soil of the downwind Queen City Summit profile yield a 137Cs/239,240Pu ratio of 0.81+/-0.02 and a 239,240Pu/238Pu ratio of 78+/-6. Clearly, an increase in 239,240Pu relative to 137Cs or 238Pu can account for these observations. There is compelling evidence that this "excess" 239,240Pu came from activities at the NTS during the aboveground testing of nuclear devices, more than likely from safety tests, some 40 years ago, and/or during the interim by the wind-driven resuspension of contaminated surface soil on the NTS and its transport off-site. Moreover, the two concentration profiles show that high percentages of both of these elements are retained for decades in the upper few centimeters of soil in Nevada's desert environment.

Cesium↗
PubMed2002

Plutonium and other alpha emitters in mushrooms from Poland, Spain and Ukraine.

The paper presents results on Pu, U and Th isotope activity concentration measurements in some mushroom samples collected in Poland, Spain and Ukraine. The sampling sites differ a lot with regard to observed levels of Pu, its origin and isotope ratios as well as the environmental properties. Some of the Polish samples were collected in the northeastern part of the country with up to 30 Bq/m2 of Chernobyl Pu deposition. Other Polish and the Spanish samples are from areas with almost exclusively global fallout Pu present. Ukrainian samples were collected in a highly contaminated area with a deposition of about 3.7 kBq/m2 of Chernobyl (239-240)Pu. The maximum (239+240)Pu activity concentration was found equal to (54+/-4) Bq/kg (dw--dry weight) for a Ukrainian Cantharellus cibarius sample. Ukrainian samples have an extremely high radiocesium level, with maximum of (51+/-4) MBq/kg (dw). The maximum (239+240)Pu activity concentration for Polish samples was (81+/-5) mBq/kg (dw) for Xerocomus badius. From the isotopic ratio in this sample it can be concluded that Chernobyl fallout is the origin of Pu. More than twice as large was the Spanish maximum for Hebeloma cylindrosporum but with only global fallout Pu. Some aspects of the transfer of nuclides to fruit bodies is discussed and in some cases the transfer factors or aggregation coefficients were calculated. Especially high transfer factors were found for Hebeloma cylindrosporum from Spain.

Agaricales↗